Microfluidic delivery member with filter and method of forming same

ABSTRACT

Embodiments are directed to microfluidic refill cartridges and methods of assembling same. The microfluidic refill cartridges include a microfluidic delivery member that includes a filter for filtering fluid passed therethrough. The filter may be configured to block particles above a threshold size to prevent blockage in the nozzles. For instances, particles having a dimension that is larger than the diameter of the nozzles can block or reduce fluid flow through the nozzle.

BACKGROUND

1. Technical Field

Embodiments are directed to microfluidic refillable cartridges thatinclude a microfluidic delivery member and methods of making and usingthe same.

2. Description of the Related Art

Fluid delivery systems that include refill cartridges are currentlybeing used in the printer industry. Many printers, including 3Dprinters, use replaceable inkjet cartridges that incorporate an inkreservoir and a print head for delivering ink from the reservoir to thepaper. The print head includes nozzles with very small openings.Particles in the cartridges, such as contaminants in the fluid, canblock the nozzles, preventing the cartridge from operating properly.

BRIEF SUMMARY

Embodiments are directed to microfluidic refill cartridges and methodsof assembling same. The microfluidic refill cartridges include amicrofluidic delivery member that includes a filter for filtering fluidpassed therethrough. The filter may be configured to block particlesabove a threshold size to prevent blockage in the nozzles. Forinstances, particles having a dimension that is larger than the diameterof the nozzles can block or reduce fluid flow through the nozzle.

Additionally, it was realized that during assembly of the microfluidicrefill cartridges contaminants other than those found in the fluid canalso block the nozzle. For instance, contaminants during the assemblyprocess can block one or more nozzles or fluid paths to the nozzles.Therefore, even if a filter is assembled into the microfluidic refillcartridge, some particles may already be downstream from the filter. Inthat regard, when the microfluidic delivery member is operated, thecontaminants that are downstream from the filter and have a dimensionthat is greater than the diameter of the nozzle, may block the nozzleand thus prevent the nozzle from operating properly.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

In the drawings, identical reference numbers identify similar elements.The sizes and relative positions of elements in the drawings are notnecessarily drawn to scale.

FIG. 1 is a schematic isometric view of a microfluidic delivery systemin accordance with one embodiment.

FIGS. 2A-2B are schematic isometric views of a microfluidic refillcartridge and a holder in accordance with one embodiment.

FIG. 3 is a cross-section schematic view of line 3-3 in FIG. 2A.

FIG. 4 is a cross-section schematic view of line 4-4 in FIG. 2B.

FIGS. 5A-5B are schematic isometric views of a microfluidic deliverymember in accordance with an embodiment.

FIG. 5C is an exploded view of the structure in FIG. 5A.

FIG. 6 is a schematic top view of a die in accordance with oneembodiment.

FIG. 7A is a cross-section schematic view of line 7-7 in FIG. 6.

FIG. 7B is an enlarged view of a portion of FIG. 7A.

FIG. 8A is a cross-section schematic view of line 8-8 in FIG. 6.

FIG. 8B is an enlarged view of a portion of FIG. 8A.

FIG. 9 is a cross-section schematic view of a fluid path of amicrofluidic refill cartridge in accordance with one embodiment.

FIG. 10 is a flow chart illustrating a method of assembling amicrofluidic delivery member in accordance with one embodiment.

FIGS. 11A-11C are schematic illustrations of a method of applyingadhesive to a surface of a PCB strip in accordance with one embodiment.

FIG. 12 is a cross-section schematic view of a fluid path into amicrofluidic delivery member in accordance with another embodiment.

FIG. 13 is a cross-section schematic view of a fluid path into amicrofluidic delivery member in accordance with another embodiment.

FIG. 14 is a cross-section schematic view of a fluid path into amicrofluidic delivery member in accordance with yet another embodiment.

DETAILED DESCRIPTION

FIG. 1 illustrates a microfluidic delivery system 10 in accordance withone embodiment of the disclosure. The microfluidic delivery system 10includes a housing 12 having an upper surface 14, a lower surface 16,and a body portion 18 between the upper and lower surfaces. The uppersurface of the housing 12 includes a first hole 20 that places anenvironment external to the housing 12 in fluid communication with aninterior portion 22 of the housing 12. The interior portion 22 of thehousing 12 includes a holder member 24 that holds a removablemicrofluidic refill cartridge 26. As will be explained below, themicrofluidic delivery system 10 is configured to use thermal energy todeliver fluid from within the microfluidic refill cartridge 26 to anenvironment external to the housing 12.

Access to the interior portion 22 of the housing is provided by anopening 28 in the body portion 18 of the housing 12. The opening 28 isaccessible by a cover or door 30 of the housing 12. In the illustratedembodiment, the door 30 rotates to provide access to the opening 28.Although the opening and door are located on the body portion of thehousing, it is to be appreciated that the opening and door may also belocated on the upper surface and the lower surface of the housing.Furthermore, it is to be appreciated that in other embodiments, thehousing has two or more separable parts for providing access to theinterior portion.

The holder member 24 includes an upper surface 32 and a lower surface 34that are coupled together by one or more sidewalls 36 and has an openside 38 through which the microfluidic refill cartridge 26 can slide inand out. The upper surface 32 of the holder member includes an opening40 that is aligned with the first hole 20 of the housing 12.

The holder member 24 holds the microfluidic refill cartridge 26 inposition when located therein. In one embodiment, the holder member 24elastically deforms, thereby gripping the microfluidic refill cartridge26 in place when located in the holder member. In another embodiment,the holder member 24 includes a locking system (not shown) for holdingthe microfluidic refill cartridge in place. In one embodiment, thelocking system includes a rotatable bar that extends across the openside of the holder member to hold the microfluidic refill cartridge inplace.

The housing 12 includes conductive elements (not shown) that coupleelectrical components throughout the system as is well known in the art.The housing 12 may further include connection elements for coupling toan external or internal power source. The connection elements may be aplug configured to be plugged into an electrical outlet or batteryterminals. The housing 12 may include a power switch 42 on a front ofthe housing 12.

FIG. 2A shows the microfluidic refill cartridge 26 in the holder member24 without the housing 12, and FIG. 2B shows the microfluidic refillcartridge 26 removed from the holder member 24. A circuit board 44 iscoupled to the upper surface 32 of the holder member by a screw 46. Aswill be explained in more detail below, the circuit board 44 includeselectrical contacts 48 (FIG. 3) that electrically couple to contacts ofthe microfluidic refill cartridge 26 when the cartridge is placed in theholder member. The electrical contacts 48 of the circuit board 44 are inelectrical communication with the conductive elements.

FIG. 3 is a cross-section view of the microfluidic refill cartridge 26in the holder member 24 along the line 3-3 shown in FIG. 2A. Withreference to FIG. 2B and FIG. 3, the microfluidic refill cartridge 26includes a reservoir 50 for holding a fluid 52. The reservoir 50 may beany shape, size, or material configured to hold any number of differenttypes of fluid. The fluid held in the reservoir may be any liquidcomposition. In one embodiment, the fluid is an oil, such as a scentedoil. In another embodiment, the fluid is water. It may also be alcohol,a perfume, a biological material, a polymer for 3-D printing, or otherfluid.

A lid 54, having an inner surface 56 and an outer surface 58, is securedto an upper portion 60 of the reservoir 50 to cover the reservoir 50.The lid 54 may be secured to the reservoir in a variety of ways known inthe art. In some embodiments, the lid 54 is releasably secured to thereservoir 50. For instance, the lid 54 and the upper portion 60 of thereservoir 50 may have corresponding threads, or the lid 54 may snap ontothe upper portion 60 of the reservoir 54. Between the lid 54 and thereservoir 50 there may be an O-ring 62 for forming a seal therebetween.The seal may prevent fluid from flowing therethrough as well as preventevaporation of the fluid to an external environment.

A microfluidic delivery member 64 is secured to an upper surface 66 ofthe lid 54 of the microfluidic refill cartridge 26 as is best shown inFIG. 2B. The microfluidic delivery member 64 includes an upper surface68 and a lower surface 70 (see also FIG. 4). A first end 72 of the uppersurface 68 includes electrical contacts 74 for coupling with theelectrical contacts 48 of the circuit board 44 when placed in the holdermember 24. As will be explained in more detail below, a second end 76 ofthe microfluidic delivery member 64 includes a fluid path for deliveringfluid therethrough.

In reference to FIG. 3, inside the reservoir 50 is a fluid transportmember 80 that has a first end 82 in the fluid 52 in the reservoir and asecond end 84 that is above the fluid 52. The fluid 52 travels from thefirst end 82 of the fluid transport member 80 to the second end 84 bycapillary action. In that regard, the fluid transport member 80 includesone or more porous materials that allow the fluid to flow by capillaryaction. The construction of the fluid transport member 80 permits fluidto travel through the fluid transport member 80 against gravity. Fluidcan travel by wicking, diffusion, suction, siphon, vacuum, or othermechanism. The second end 84 of the transport member is located belowthe microfluidic delivery member 64. The fluid transport member 80delivers fluid 52 from the reservoir 50 toward the microfluidic deliverymember 64.

As best shown in FIG. 4, the second end 84 of the fluid transport member80 is surrounded by a transport cover 86 that extends from the innersurface of the lid 54. The second end 84 of the fluid transport member80 and the transport cover 86 form a chamber 88. The chamber 88 may besubstantially sealed between the transport cover 86 and the second end84 of the fluid transport member 80 to prevent air from the reservoir 50from entering the chamber 88.

Above the chamber 88 is a first through hole 90 in the lid 54 thatfluidly couples the chamber 88 above the second end 84 of the fluidtransport member 80 to a second through hole 78 of the microfluidicdelivery member 64. The microfluidic delivery member 64 is secured tothe lid 54 above the first through hole 90 of the lid 54 and receivesfluid therefrom.

In some embodiments, the fluid transport member 80 includes a polymer;non-limiting examples include polyethylene (PE), including ultra-highmolecular weight polyethylene (UHMW), polyethylene terephthalate (PET),polypropylene (PP), nylon 6 (N6), polyester fibers, ethyl vinyl acetate,polyvinylidene fluoride (PVDF), and polyethersulfone (PES),polytetrafluroethylene (PTFE). The fluid transport member 80 may be inthe form of woven fibers or sintered beads. It is also to be appreciatedthat the fluid transport member of the present disclosure is of smallersize than is typically used for fluid transport members for refillablecartridges.

As shown in FIG. 4, the fluid transport member 80 may include an outersleeve 85 that surrounds radial surfaces of the fluid transport member80 along at least a portion of its length while keeping the first andsecond ends 82, 84 of the fluid transport members 80 exposed. The sleeve85 may be made from a non-porous material or a material that is lessporous than the fluid transport member 80. In that regard, the sleeve 85may prevent or at least reduce air in the reservoir from entering thefluid transport member 80 by radial flow.

The outer sleeve 85 may be a material that is wrapped around the fluidtransport member 80. In other embodiments, the sleeve 85 is formed onthe fluid transport member 80 in an initial liquid state that dries orsets on the fluid transport member. For instance, the material may besprayed on the fluid transport member or the fluid transport member maybe dipped into a liquid material that dries. The outer sleeve may be apolymer sheet, a Teflon tape, a thin plastic layer, or the like. Teflontape has particular benefits since it provides a fluid-tight seal, isflexible to wrap, is strong, and also makes it easy to slip around thefluid transport member 80.

The fluid transport member 80 may be any shape that is able to deliverfluid 52 from the reservoir 50 to the microfluidic delivery member 64.Although the fluid transport member 80 of the illustrated embodiment hasa width dimension, such as diameter, that is significantly smaller thanthe reservoir, it is to be appreciated that the diameter of the fluidtransport member 80 may be larger and in one embodiment substantiallyfills the reservoir 50.

FIGS. 5A and 5B, respectively, are top and bottom views of themicrofluidic delivery member 64 in accordance with one embodiment. FIG.5C illustrates the microfluidic delivery member 64 in exploded view. Themicrofluidic delivery member 64 includes a rigid planar circuit board,which can be a printed circuit board (PCB) 106 having the upper andlower surfaces 68, 70. The PCB 106 includes one or more layers ofinsulative and conductive materials as is well known in the art. In oneembodiment, the circuit board includes FR4, a composite materialcomposed of woven fiberglass cloth with an epoxy resin binder that isflame resistant. In other embodiments, the circuit board includesceramic, glass or plastic. The PCB 106 may include a vent hole 144 thatis in fluid communication with the reservoir 50 to equalize pressure inthe reservoir 50 as fluid 52 is removed from the reservoir.

The upper surface 68 of the second end 76 of the printed circuit board106 includes a semiconductor die 92 above the second through hole 78 andleads 112 located proximate the die 92. Electrical contacts 74 at thefirst end 72 of the microfluidic delivery member 64 are coupled to oneor more of the leads 112 at the second end 76 by electrical traces (notshown).

The upper and lower surfaces 68, 70 of the PCB 106 may be covered with asolder mask 124 as shown in the cross-section view of FIG. 4. Openingsin the solder mask 124 may be provided where the leads 112 arepositioned on the circuit board or at the first end 72 where theelectrical contacts 74 are formed. The solder mask 124 may be used as aprotective layer to cover electrical traces.

The die 92 is secured to the upper surface 68 of the printed circuitboard 106 by any adhesive material 104 configured to hold thesemiconductor die to the PCB. The adhesive material may be an adhesivematerial that does not readily dissolve by the fluid in the reservoir.In some embodiments, the adhesive material is activated by heat or UV.In some embodiments, a mechanical support (not shown) may be providedbetween a bottom surface 108 of the die 92 and the upper surface 68 ofthe printed circuit board 106.

As best shown in FIG. 6, the die 92 includes a plurality of bond pads109 that are electrically coupled to one or more of the leads 112 byconductive wires 110. That is, a first end of the conductive wires 110is coupled to a respective bond pad 109 of the die 92 and a second endof the conductive wires 110 is coupled to a respective lead 112. Thus,the bond pads 109 of the die 92 are in electrical communication with theelectrical contacts 74 of the microfluidic delivery member 64. A moldingcompound or encapsulation material 116 may be provided over theconductive wires 110, bond pads 109, and leads 112, while leaving acentral portion 114 of the die 92 exposed.

As best shown in FIG. 4, the die 92 includes an inlet path 94 in fluidcommunication with the second through hole 78 on the second end 76 ofthe microfluidic delivery member 64. With reference also to FIGS. 7 and8, which illustrate corresponding cross sections of the die of FIG. 6,the inlet path 94 of the die 92 is in fluid communication with a channel126 that is in fluid communication with individual chambers 128 andnozzles 130, forming a fluid path through the die 92. Above the chambers128 is a nozzle plate 132 that includes the plurality of nozzles 130. Ina first embodiment, each nozzle 130 is located above a respective one ofthe chambers 128 and is an opening in the nozzle plate 132 that is influid communication with an environment outside of the microfluidicrefill cartridge 26. The die 92 may have any number of chambers 128 andnozzles 130, including one chamber and nozzle. In the illustratedembodiment, the die 92 includes 18 chambers 128 and 18 nozzles 130, eachchamber associated with a respective nozzle. Alternatively, it can have10 nozzles and 2 chambers, one chamber providing fluid for a bank offive nozzles. It is not necessary to have a one-to-one correspondencebetween the chambers and nozzles. In one embodiment, the nozzle plate132 is 12 microns thick. In some embodiments, the nozzle 130 has adiameter between 20-30 microns.

As is best shown in FIG. 8B, proximate each chamber 128 is a heatingelement 134 that is electrically coupled to and activated by anelectrical signal being provided by a bond pad of the die 92. In use,when the fluid in each of the chambers 128 is heated by the heatingelement 134, the fluid vaporizes to create a vapor bubble. The expansionthat creates the vapor bubble causes a droplet to form and eject fromthe nozzle 130. Other ejection elements may be used for causing fluid tobe ejected from the nozzle 130. For instance, piezoelectric elements orultrasonic fluid ejection elements may be used to cause fluid to beejected through the nozzles 130 as is well known in the art.

Each nozzle 130 is in fluid communication with the fluid in thereservoir by a fluid path that includes the first end 82 of the fluidtransport member 80, through the transport member to the second end 84,the chamber 88 above the second end 84 of the transport member, thefirst through hole 90 of the lid, the second through hole 78 of the PCB,through the inlet path 94 of the die, through the channel 126, to thechamber 128, and out of the nozzle 130 of the die 92.

In reference again to FIG. 4, a filter 96 is positioned between thechamber 88 and inlet path 94 of the die 92. The filter 96 is configuredto prevent at least some particles from passing therethrough, therebypreventing and/or reducing blockage in the downstream fluid path, mostparticularly in the nozzles 130 of the die 92. In some embodiments, thefilter 96 is configured to block upstream particles that are greaterthan one third of the diameter of the nozzles.

The filter 96 may be any material that blocks particles from flowingtherethrough and does not break apart when exposed to the fluid, whichcould create further particles to block the fluid path. In oneembodiment, the filter 96 is a stainless steel mesh. In otherembodiments, the filter 96 is a randomly weaved mesh and may comprisepolypropylene or silicon.

Referring now to FIG. 9, there is provided a close-up view of a portionof a microfluidic refill cartridge 26 illustrating a flow path with afilter 96 between the second end 84 of the fluid transport member 80 andthe die 92 in accordance with one embodiment.

The filter 96 is separated from the lower surface 70 of the microfluidicdelivery member 64 proximate the second through hole 78 by a firstmechanical spacer 98. The first mechanical spacer 98 creates a gap 99between the lower surface 70 of the microfluidic delivery member 64 andthe filter 96 proximate the second through hole 78. In that regard, theoutlet of the filter 96 is greater than the diameter of the secondthrough hole 78 and is offset therefrom so that a greater surface areaof the filter 96 can filter fluid than would be provided if the filter96 was attached directly to the lower surface 70 of the microfluidicdelivery member 64 without the mechanical spacer 98. It is to beappreciated that the mechanical spacer 98 allows suitable flow ratesthrough the filter 96. That is, as the filter 96 clogs up withparticles, the filter 96 will not slow down the fluid being provided tothe second through hole 78. In one embodiment, the outlet of the filteris 4 mm² or larger and the first mechanical spacer 98 is between 100 and700 microns thick.

The first mechanical spacer 98 may be a separate rigid support, aprotrusion formed on the lower surface 70 of the microfluidic deliverymember 64, such as the solder mask, or adhesive material that conformsto a shape that provides an adequate distance between the filter 96 andthe lower surface 70 of the microfluidic delivery member 64. Theadhesive material may be an adhesive material that does not readilydissolve by the fluid in the reservoir. In some embodiments, theadhesive material is activated by heat or UV. The adhesive material maybe the same or different from the adhesive material used to secure thedie 92 to the microfluidic delivery member 64.

It is to be appreciated that in some embodiments, the fluid transportmember 80 is made from one or more materials that do not react with thefluid. Thus, the fluid transport member 80 does not introducecontaminants into the fluid that could block fluid flow through themicrofluidic delivery member 64.

As shown in FIG. 9, the second through hole 78 of the microfluidicdelivery member 64 may include a liner 100 that covers exposed sidewalls102 of the PCB 106. The liner 100 may be any material configured toprotect the PCB 106 from breaking apart, such as to prevent fibers ofthe PCB from separating. In that regard, the liner 100 may protectagainst particles from the PCB 106 entering into the fluid path andblocking the nozzles 130. For instance, the sidewalls 102 of the secondthrough hole 78 may be lined with a material that is less reactive tothe fluid in the reservoir than the material of the PCB 106. In thatregard, the PCB 106 may be protected as the fluid passes therethrough.In one embodiment, the sidewalls 102 of the second through hole 78 arecoated with a metal material, such as gold. As mentioned above, theupper and lower surfaces 68, 70 of the PCB 106 may be covered by asolder mask, which can protect the PCB material from the fluid.

FIG. 10 illustrates a method 150 of assembling a plurality ofmicrofluidic delivery members, such as the microfluidic delivery member64 shown in FIG. 9, in accordance with one embodiment. The method 150includes applying adhesive material 104 to a bottom surface of a PCBstrip 106 a as shown by step 152. The PCB strip 160 a will have openingsformed therein for the second through holes 78. The sidewalls of theopenings may be lined as discussed above.

At step 154, filters 96 are secured to the lower surface 70 of the PCBstrip 106 a using the adhesive 104. The filters 96 are secured at firstmechanical spacers 98. That is, the first mechanical spacers 98 may bealready secured or formed on the lower surface 70 of the PCB strip 106a. For instance, the mechanical spacer 98 may be formed from a soldermask material that is provided on the lower surface 70 of the PCB strip106 a. In that regard, the solder mask material is thicker at locationson the PCB strip 106 a for forming the mechanical spacer 98.Alternatively, the first mechanical spacer 98 may attached to the lowersurface 70 of the PCB strip 106 a using the adhesive. Then the filter 96is secured to the first mechanical spacer 98 with further adhesive. Itis to be appreciated that the filter 96 may be attached directly to thelower surface 70 of the PCB strip 106 a with the adhesive 104 acting asthe first mechanical spacer 98 as recited above. If the adhesive isactivated by heat or UV, the method would further include a baking stepor UV exposure to secure the filter and first mechanical spacer to thebottom surface of the PCB.

Adhesive 104 may be applied to the upper surface 68 of the PCB strip 106a at step 156. Semiconductor dice, such as the die 92, are secured tothe upper surface 68 of the PCB strip 106 a using the adhesive 104 atstep 158. Again, the securing step may include a baking step or UVexposure to activate the adhesive.

It is to be appreciated that the fluid path through the second throughhole 78 of the PCB strip 106 a between the semiconductor die 92 and thefilter 96 is quite small. In that regard, there is little surface areafor contaminants to be located downstream of the filter 96, that is,between the filter 96 and the nozzles 130. Additionally, the die and thefilter are attached to the PCB without other steps therebetween, therebyreducing the chances of contaminants from getting downstream of thefilter. In that regard, the above steps may be performed quickly.Finally, the steps indicated above may be performed in a class 1000cleanroom environment, reducing the number of contaminants in the airand thereby reducing the likelihood of contaminants from getting in thefluid path downstream from the filter 96.

The method continues with electrically coupling the dice 92 to the PCBstrip 106 a by coupling first ends of conductive wires 110 to bond pads109 on the die 92, respectively, and coupling second ends of theconductive wires 110 to the leads 112 of the PCB strip 106 a,respectively at step 160. The bond pads, conductive wires, and the leadsare encapsulated with an encapsulation material 116 at step 162. The PCBstrip 106 a may be singulated by dicing, such as by, laser cutting,sawing, and the like, into a plurality of microfluidic delivery members64 as indicated by step 164.

In one embodiment, the adhesive material 104 may be applied to the uppersurface 68 and/or lower surface 70 of the PCB strip 106 a using screenprinting techniques as illustrated in FIGS. 11A-11C. In that regard, ascreen stencil 165 may be placed over the upper surface of the PCB strip106 a. The screen stencil 165 has openings 166 or a mesh layer atlocations in which the adhesive is to be applied to the PCB strip 106 a.Adhesive 104 is deposited on the screen stencil 165 as shown in FIG.11A, and a squeegee 167 may be used to spread the adhesive 104 in theopenings 166 or mesh layer as shown in FIG. 11B. The squeegee 167 may bepassed over the screen stencil 165 multiple times in order to fill theopenings 166 or mesh layers in the screen stencil 165. The screenstencil 165 is then removed, and the assembly of the microfluidicdelivery members 64 continues as indicated above.

FIG. 12 shows a microfluidic delivery member 64 a in accordance withanother embodiment. The microfluidic delivery member 64 a has the filter96 and the die 92 on the same side, the upper surface 68, of the PCB106. In particular, the filter 96 is secured to the upper surface 68 ofthe PCB 106 and the die 92 is secured to the filter 96. A firstmechanical spacer 98 a is provided between the upper surface 68 of thePCB 106 and the filter 96 to allow a greater surface area of flowtherethrough. A second mechanical spacer 98 b may also be providedbetween the filter 96 and the die 92. The first mechanical spacer 98 acreates a gap 101 between the filter 96 and the upper surface 68 of thePCB 106. Similarly, the second mechanical spacer 98 b creates a gap 103between the filter 96 and the die 92. Thus, the surface areas of theinlet and outlet of the filter 96 are larger than the inlet path 94 ofthe die 92. In that regard, as the filter 96 becomes clogged withparticles from the fluid, the flow through the filter 96 does not affectthe fluid flow through the inlet path 94 of the die 92. In someembodiments, the filter 96 may be sealed, such as by a sealant 105, onthe outer edges to prevent fluid from flowing therethrough. Although thefilter 96 is shown as the same size as the die 92, the filter 96 mayalso be smaller or larger than the die 92.

FIG. 13 is a cross-section schematic view of a fluid path into amicrofluidic delivery member 64 b in accordance with another embodiment.In the microfluidic delivery member 64 b, the liner 107 a and the firstmechanical spacer 107 b are formed of the same material and may beintegrally formed. The liner 107 a and the first mechanical spacer 107 bperform the same function as the liner 100 and the first mechanicalspacer 96. In one embodiment, the liner 107 a and the first mechanicalspacer 107 b are formed by an insert molding process in which the filter96 is inserted into the mold and the material for forming the liner 107a and the first mechanical spacer 107 b is injected into the mold andconfigured to adhere to the filter 96. The liner 107 a and the firstmechanical spacer 107 b may be formed from a plastic material, includinga polymer, such as polyethylene terephthalate (PET),

By attaching the filter to the die, the microfluidic delivery member hasfew a small pathways that could have contaminants therein that may blockthe filter. Furthermore, the filter and the die may be assembled insteps that are close together, which would also reduce the likelihood ofcontaminants getting therein.

FIG. 14 is a cross-section schematic view of a fluid path into amicrofluidic delivery member 64 c in accordance with yet anotherembodiment. In the microfluidic delivery member 64 c, a filter 96 a isformed integrally in a substrate material, such as a silicon substrate.The filter 96 a includes a filter portion 171 a filter body 173. Thefilter body 173 is secured to a bottom surface 108 of the die 92 by anadhesive material (not shown), including a paste, a glue, double sidedtape or any other suitable adhesive. The filter portion 171 includes aplurality of holes formed in the substrate material that are configuredto filter fluid that flows therethrough. In one embodiment the diameterof the holes is about one half of the diameter of the nozzles 130. Inone embodiment, the holes are 10-12 microns.

Above the filter portion 171 is a channel 175 formed in the substratematerial. The channel 175 is wider than the inlet 94 to the die 92. Thefilter body 173 thus can act as a spacer, such as the first mechanicalspacer discussed above, to the die 92. In that regard, as the filterportion 171 becomes blocked (i.e. holes in the filter portion 171 becomeclogged with particles), the fluid flow through the inlet 94 may not bereduced.

The filter 96 a may be formed by first forming the channel 175. Inparticular, a patterned mask layer may be formed over a first surface ofthe substrate and the substrate may be etched to a particular depth asis well known in the art, thereby forming the channel 175. The depth ofthe channel 175 may be any depth that provides adequate flow to theinlet 94 as the filter portion 171 clogs up with particles. In oneembodiment, the channel 175 is 100 microns deep into the substrate andthe width of the channel is 3-4 millimeters wider than the width of theinlet 94 to the die 92.

The plurality of holes of the filter portion 171 may also be formedusing a patterned mask layer and etching as is well known in the art.The mask layer may be photoresist and the etching may be either wet ordry etch. In some embodiments, the filter portion 171 is about 100microns thick.

It is to be appreciated that the die 92 may include a channel (notshown), such as the channel 175 of the filter 96 a. In that regard, thefilter 96 a may not include the channel 175. In one embodiment, however,the filter 96 a may also include channel 175. Thus, the channel of thedie 92 and the channel 175 of the filter 96 a together may provideadequate flow rates to the inlet 94 of the die 92.

Prior to use, the microfluidic refill cartridge 26 may be primed toremove air from the fluid path. During priming, air in the fluid path isreplaced with fluid from the reservoir 50. In particular, fluid may bepulled up from the fluid transport member 80 to fill the chamber 88, thefirst through hole 90 of the lid 54, the second through hole 78 of themicrofluidic delivery member 64, the inlet path 94 of the die 92, thechannel 126, and the chamber 128. Priming may be performed by applying avacuum force through the nozzles 130. The vacuum force is typicallyperformed with the microfluidic refill cartridge in an upright positionfor a few seconds. In some embodiments, a vacuum force is applied for 30to 60 seconds. The microfluidic refill cartridge 26 may also be primedby applying air pressure through a hole (not shown) in the lid 54 of thecartridge that is in fluid communication with the reservoir 50 toincrease the air pressure on the fluid in the reservoir 50, therebypushing fluid up the fluid transport member 80 through the fluid path.It is to be appreciated that the hole is sealed with a cover 120 (seeFIG. 2B), such as elastic material that fits into at least a portion ofthe hole, after priming.

Once primed, the nozzles 130 may be sealed to prevent de-priming of thefluid path. De-priming may occur when air enters the fluid path. In thatregard, a cover (not shown) may be placed over the nozzles 130 toprevent air from outside of the microfluidic refill cartridge 26 fromentering the fluid path. It is to be appreciated that in someembodiments, the outer sleeve 85 of the fluid transport member 80 mayprevent de-priming of the fluid transport member 80. That is, the sleeve85 prevents air from entering the fluid transport member 80 along itsradial surface.

Once primed, during use, when fluid exits the nozzle 130, fluid from thereservoir 50 is pulled up through the fluid path by capillary action. Inthat regard, as fluid exits the chamber 128, fluid automatically refillsthe chamber 128 by being pulled through the fluid path by capillaryaction.

As indicated above, the transport cover 86 in combination with thesecond end 84 of the fluid transport member 80 form a seal that fluidlyisolates the chamber 88 from the reservoir 50 to assist in keeping themicrofluidic refill cartridge 26 primed. It is to be appreciated thatthe chamber 88 may be at a different pressure than the reservoir 50.

It is to be appreciated that in many embodiments, the fluid transportmember 80 is configured to self-prime. That is, fluid may travel fromthe first end 82 of the fluid transport member 80 to the second end 84without the aid of a vacuum force or air pressure as discussed above.

The microfluidic refill cartridge 26 includes a vent path that placesthe reservoir in fluid communication with the external environment ofthe microfluidic refill cartridge 26. The vent path equalizes the airpressure in the reservoir 50 with the air pressure of the externalenvironment. That is, as fluid exits the microfluidic refill cartridge26 through the nozzles 130, air from the external environment fills thespace in the reservoir 50 that is made by the removed fluid. In thatregard, the air pressure above the fluid in the reservoir remains atatmosphere. This allows the microfluidic refill cartridge to remainprimed and prevents or at least reduces back pressure in the fluid path.That is, by equalizing the pressure in the reservoir, the reservoir doesnot create a vacuum that pulls the fluid from the fluid path back intothe reservoir.

Upon depletion of the fluid in the reservoir 50, the microfluidic refillcartridge 26 may be removed from the housing 10 and replaced withanother microfluidic refill cartridge 26.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

1. A microfluidic delivery member comprising: a printed circuit boardhaving first and second surfaces and a through hole extending from thefirst surface to the second surface; a filter secured to the secondsurface of the printed circuit board over the through hole; and asemiconductor die having first and second surfaces and an inlet path,the semiconductor die secured to the first surface of the printedcircuit board with the inlet path in fluid communication with thethrough hole of the printed circuit board, the second surface of the dieincluding a plurality of nozzles that are in fluid communication withthe inlet path.
 2. The microfluidic delivery member of claim 1 whereinthe filter includes at least one of a stainless steel mesh, randomlyweaved mesh, polypropylene or a substrate material with a plurality ofholes.
 3. The microfluidic delivery member of claim 1 wherein theplurality of nozzles have a diameter between 15 and 30 microns.
 4. Themicrofluidic delivery member of claim 3, wherein the filter isconfigured to filter particles greater than one third of the diameter ofthe nozzles.
 5. The microfluidic delivery member of claim 1, furthercomprising a mechanical spacer located between the filter and the secondsurface of the printed circuit board, to space the filter from thesecond surface of the printed circuit board by a first distance.
 6. Themicrofluidic delivery member of claim 5, wherein the first distance isbetween 100 and 700 microns from the second surface of the printedcircuit board.
 7. The microfluidic delivery member of claim 5, furthercomprising a liner on sidewalls of the through hole, the liner beingintegral with the mechanical spacer.
 8. The microfluidic delivery memberof claim 5, wherein the mechanical spacer is one of a raised portion ofsolder mask formed on the printed circuit board and adhesive material.9. A microfluidic delivery member comprising: a printed circuit boardhaving first and second surfaces and a through hole extending from thefirst surface to the second surface; a filter secured to the printedcircuit board over the through hole; and a semiconductor die havingfirst and second surfaces and an inlet path, the semiconductor diesecured to the filter with the inlet path in fluid communication withthe through hole of the printed circuit board through the filter, thesecond surface of the die including a plurality of nozzles that are influid communication with the inlet path.
 10. The microfluidic deliverymember of claim 9 further comprising first and second mechanicalspacers, the first mechanical spacer being located between the printedcircuit board and the filter and the second mechanical spacer beinglocated between the filter and the die.
 11. The microfluidic deliverymember of claim 10 wherein the first mechanical spacer is a raisedportion of solder mask formed on the printed circuit board.
 12. Themicrofluidic delivery member of claim 10 wherein the first and secondmechanical spacers are between 100 and 700 microns thick.
 13. Themicrofluidic delivery member of claim 9 further comprising an adhesivematerial that secures the filter to the printed circuit board.
 14. Amethod comprising: applying adhesive material to a first surface of aprinted circuit board strip; securing a plurality of filters to thefirst surface of the printed circuit board strip using the adhesivematerial, the plurality of filters covering a plurality of throughholes, respectively, in the printed circuit board; applying adhesivematerial to a second surface of the printed circuit board strip; andsecuring a plurality of semiconductor dice to the second surface of theprinted circuit board strip, the plurality of semiconductor dicecovering the plurality of through holes, respectively, the plurality ofsemiconductor dice including an inlet path in fluid communication withthe plurality of through holes, respectively, and having nozzles forexpelling a fluid.
 15. The method of claim 14, further comprisingforming the plurality of through holes in the printed circuit boardstrip.
 16. The method of claim 14, wherein securing the plurality offilters comprises attaching the filters and exposing the adhesivematerial to heat or ultraviolet radiation to set the adhesive material.17. The method of claim 14, wherein the applying the adhesive materialcomprises using a screen printing technique to apply the adhesivematerial.
 18. The method of claim 14, further comprising placingmechanical spacers between the filters and the first surface of theprinted circuit board strip.
 19. The method of claim 18, wherein placingthe mechanical spacers comprises forming a solder mask layer on theprinted circuit board strip, the solder mask layer including a raisedportion around each through hole for forming the mechanical spacers. 20.The method of claim 14, further comprising separating the printedcircuit board strip into a plurality of microfluidic delivery members.21. The method of claim 14, wherein each filter is a stainless steelmesh.